Cross Ref > Language Basics

In C# commands and variable names are case sensitive. The following does NOT:

messagebox.Show("hello");  //Does not compile!

The first time you type any other case for commands or variables, VS.Net will change it to the accepted or defined case. For example, if you type messagebox.show it is converted to MessageBox.Show. Once corrected, you can break it again by editing MessageBox to messagebox and the compiler will give you an error.

MessageBox.Show("hello");

 C# Case Sensitivity (Yes)  

JavaScript is case sensitive. Change the case, and it no longer works! Notice the "W" in "Write" is capitalized.

<script language=JavaScript> 
<!--
document.Write("Hello"); //Does not work! 
//--> 
</script>

Variable names are case sensitive.

<script language=JavaScript> 
<!--
document.write("Hello"); 
//--> 
</script>

C# uses braces {} to indicate a code block of more than one line. For one line of code, the braces are optional.

I prefer to put the opening { and the closing } on their own line only because most of the examples I see do this. As opposed to C++, Java, and JavaScript where I put the opening bracket at the end of the first line (which I actually prefer).

int DoSomething()

{

 int a = 1;

 int b = 2;

 return a + b;

}

In html pages, you embed JavaScript code between <script> and </script> (see example). Also it's tradtional to put an HTML comment around your code too so that really old browsers don't crash (probably not all that important these days).

For JavaScript, Java, PHP, and C++, I prefer to put the first { at the end of the first line of the code block as in the example above because I see moreJavaScript codeformatted that way.

<script language="JavaScript" type="text/javascript">

<!--

function DisplayDialogLg(StrURL) {
}

if (x == -1) {

}

-->

</script>

Commenting Code
C# uses "//" for a single line comment and /* */ for a multiple line comment.

//Single line comment.

/*
Multiple line
comment.

*/

Commenting Code
JavaScript uses "//" for a single line comment and /* */ for a multiple line comment.

//This is a single line comment.
 
/*
Multiple line
comment.

*/

In C#, you define constants with the const keyword.

All constants are part of a class (no global constants) but you can make a constant public and have access to it using ClassName.ConstantName so long as you have added the class to the project. This works even without creating the class as if the public constants were static, but you cannot use the static keyword.

Constants must be of an integral type (sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, decimal, bool, or string), an enumeration, or a reference to null.

Syntax Example:   public class Convert : Object {   public const string kName = "Mike";   //You can declare multiple of the same type too: const Double kFeetToMeter = 3.2808, kMeterToFeet = .3048; }

Although JavaScript has variables, it does not have constants.

C# uses a semicolon ";" as an end of statement specifier and you can put multiple statements on a single line of code if you wish as well as split a single statement into two or more code lines.

Syntax Example:   Console.WriteLine("Hello1"); Console.WriteLine("Hello2"); Console.WriteLine("Hello3"); //Same line works too: Console.WriteLine("Hello4"); Console.WriteLine("Hello5"); //Two or more lines works too: Console. WriteLine ("Hello6");

In JavaScript, using a semicolon at the end of statements is optional. You might think a semicolon then is just another comment specifier but it is not. The semicolon is an optional end of statement specifier. To put two statements on a single code line, you must use a semicolon. However, the semicolon is optional, but probably confusing, when you break a single statement into multiple code lines.

document.write("Hello1");
document.write("Hello2");
 
//Semicolons are optional:
document.write("Hello3")
document.write("Hello4")
 
//This works too but only if you use a semicolon:
document.write("Hello5");  document.write("Hello6");
 
//Two lines also works:
document.write
  ("Hello7")

 JavaScript End of Statement (; is optional)

String literals are quoted as in "Prestwood". If you need to embed a quote use a slash in front of the quote as in \".

To specify a floating point literal between 1 and -1, you can preceed the decimal with a 0 or not (both work). In other words, preceding decimals are allowed (both .1 and 0.1). Trailing decimals are not allowed.

Console.WriteLine("Hello");
Console.WriteLine("Hello \"Mike\".");

//Does C# evaluate this simple

//floating point math correctly? No! 

if ((0.1 + 0.1 + 0.1) == 0.3)
{
  MessageBox.Show("Correct");
}
else
{
  MessageBox.Show("Not correct");
}

String literals use either an apostrophe (also known as a single quote) as in 'Prestwood' or quoted as in "Prestwood". If you need to embed an apostrophe in an apostrophe-literal or a quote in a quoted-literal, precede it with a slash as in \' and \".

Alert("Hello");

Alert("Hello \"Mike\".")

Alert('Hello');

Alert('Hello Mike\'s website.')

//Does JavaScript evaluate this simple

//floating point math correctly? No! 

if ((.1 + .1 + .1) == .3) {
 document.write("Correct")
} else {
 document.write("Not correct")
}

 JavaScript Literals (quote or apostrophe)

C++, Java, and C# all use C-like variable declaration.

C# has C-like variable declaration and although variables are case sensitive, VS.Net will auto-fix your variable names to the defined case.

C# offers many variable types. Some common types used include short, int, long, float, double, decimal, Int16, UInt16, Int32, Int64, string, and bool.

You can also specify the value when you declare a variable as in:

String FirstName = "Mike";

String LastName = "Prestwood";

Int16 Age = 42;

string FullName;

int16 Age;

double Weight;

FullName = "Mike Prestwood";

Age = 32;

Weight = 154.4;

JavaScript is a loosely typed language. Each variable is cast in usage as string, number, boolean, function, or object.

Variable names are case sensitive.

Alternatively, you can specify the value when you declare a variable:

var FirstName = "Mike";

var LastName = "Prestwood";

var Age = 42;

var FirstName;

var LastName;

var Age;